<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title></title>
    <style type="text/css">
        *{
            margin: 0;
        }

        .div01{
            width: 100px;
            height: 100px;
            background: blue;
            position: relative;

        }

        .div02{
            width: 100px;
            height: 100px;
            background: red;
            position: relative;
        }
        /*
           加position: relative;属性和不加界面没有任何变化
        */

    </style>
</head>
<body>
<div class="div01"></div>
<div class="div02"></div>
</body>
</html>
